Leaders of the Gulf Cooperation Council (GCC) are expected to meet in the coming days in Saudi Arabia in an attempt to unlock the logjam over Yemen's political crisis.

News agencies reported on Thursday that a specific day and time is not set for the gathering of foreign ministers from the six-member council. Yemen is expected to be the only topic on the agenda. News reports quote unnamed ruling party members as saying a transition of power deal could be signed on Sunday.

A GCC envoy, Secretary General Abdullatif bin Rashid al-Zayani, left Sana'a late Wednesday without the signatures of President Ali Abdullah Saleh and opposition leaders on an agreement to end the standoff and provide a transition of power.

Al-Zayani made no public comments before leaving, but news organizations quote Yemeni officials as saying Saleh objected to at least one of the opposition figures who had planned to sign the deal.

Earlier, an aid to Saleh and an opposition official said the two sides planned to sign the agreement on Wednesday. The plan offers President Saleh immunity from prosecution if he transfers power to a deputy within 30 days of signing.

In Washington on Thursday, U.S. President Barack Obama urged Saleh to follow through a peaceful transition of power.

It is the second GCC attempt to gain an agreement.

Last month, similar plans to sign the agreement stalled after Saleh refused to sign in his capacity as president, as required. He said he would only sign as head of the ruling General People's Congress party.

Meanwhile, fresh anti-government protests erupted in several cities on Wednesday. Some Yemenis observed a general strike that had been called for by opposition leaders.

The Yemeni government has attempted to crack down on protests, but thousands of anti-government demonstrators have continued to take to the streets demanding President Saleh's immediate resignation.